| From: |
| Chengguang Xu <cgxu519-AT-mykernel.net> |
| To: |
| miklos-AT-szeredi.hu, amir73il-AT-gmail.com, jack-AT-suse.cz |
| Subject: |
| [RFC PATCH 0/5] implement containerized syncfs for overlayfs |
| Date: |
| Sat, 10 Oct 2020 22:23:50 +0800 |
| Message-ID: |
| <20201010142355.741645-1-cgxu519@mykernel.net> |
| Cc: |
| linux-unionfs-AT-vger.kernel.org, linux-fsdevel-AT-vger.kernel.org, Chengguang Xu <cgxu519-AT-mykernel.net> |
| Archive-link: |
| Article |
Current syncfs(2) syscall on overlayfs just calls sync_filesystem()
on upper_sb to synchronize whole dirty inodes in upper filesystem
regardless of the overlay ownership of the inode. In the use case of
container, when multiple containers using the same underlying upper
filesystem, it has some shortcomings as below.
(1) Performance
Synchronization is probably heavy because it actually syncs unnecessary
inodes for target overlayfs.
(2) Interference
Unplanned synchronization will probably impact IO performance of
unrelated container processes on the other overlayfs.
This series try to implement containerized syncfs for overlayfs so that
only sync target dirty upper inodes which are belong to specific overlayfs
instance. By doing this, it is able to reduce cost of synchronization and
will not seriously impact IO performance of unrelated processes.
Chengguang Xu (5):
fs: introduce notifier list for vfs inode
fs: export symbol of writeback_single_inode()
ovl: setup overlayfs' private bdi
ovl: monitor marking dirty activity of underlying upper inode
ovl: impement containerized syncfs for overlayfs
fs/fs-writeback.c | 7 ++++-
fs/inode.c | 5 ++++
fs/overlayfs/inode.c | 28 +++++++++++++++++++-
fs/overlayfs/overlayfs.h | 2 ++
fs/overlayfs/ovl_entry.h | 2 ++
fs/overlayfs/super.c | 65 ++++++++++++++++++++++++++++++++++++++++++++---
fs/overlayfs/util.c | 33 ++++++++++++++++++++++++
include/linux/fs.h | 6 +++++
include/linux/writeback.h | 1 +
9 files changed, 143 insertions(+), 6 deletions(-)
--
1.8.3.1
